When a route bus has departed, a passenger who is not seated and does not hold a hand rail or a strap may fall down. Regarding an accident of a bus, there are more cases of falling accidents of a passenger than there are cases of accidents with respect to a vehicle or a pedestrian.
Patent literature 1 discloses a technology for suppressing a falling accident of passengers by determining whether the passenger is seated, and by adjusting a state of traveling of the bus in accordance with the determination result.
The inventor of the present disclosure has found that it may be difficult to sufficiently reduce the falling accidents of passengers even when a traveling state of a bus is adjusted as described in patent literature 1 if a vehicle departs when a passenger who is not seated and does not hold the hand rail or the strap is present.